Update docstrings to reflect reranking endpoint change

[ChrisJar]

Description

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.
• If adjusting docker-compose.yaml environment variables have you ensured those are mimicked in the Helm values.yaml file.

[greptile-apps]

Greptile Summary

This PR updates docstrings across the reranking module to reflect the already-implemented switch from the OpenAI-compatible /rerank endpoint to the NIM-specific /v1/ranking endpoint (with rankings/logit response shape and query: {text} / passages: [{text}] payload). Tests are also updated to assert the new payload fields (truncate, passages[0]) and response structure.

Confidence Score: 5/5

Safe to merge — all findings are minor P2 docstring polish with no functional impact.

The PR is a documentation-only change with corresponding test fixture updates. Both remaining findings are P2 style suggestions (stale top_n wording and a vLLM version qualifier), neither of which affects runtime behavior.

nemo_retriever/src/nemo_retriever/rerank/rerank.py — two minor docstring nits in the module header and _rerank_via_endpoint Returns section.

Vulnerabilities

No security concerns identified. The PR is documentation-only with aligned test fixture updates; no credential handling, input validation, or network logic was changed.

Important Files Changed

Filename	Overview
nemo_retriever/src/nemo_retriever/rerank/init.py	Docstring-only update: /rerank → /v1/ranking; correct and complete.
nemo_retriever/src/nemo_retriever/rerank/rerank.py	Docstring updates align with the /v1/ranking endpoint and rankings/logit response shape; stale top_n reference in the Returns section and potentially misleading vLLM version hint remain.
nemo_retriever/src/nemo_retriever/retriever.py	One-line docstring update for reranker_endpoint; accurate and complete.
nemo_retriever/tests/test_nemotron_rerank_v2.py	Test fixtures updated to rankings/logit response shape; new assertions for truncate and passages[0] fields added; all changes consistent with implementation.

Sequence Diagram

sequenceDiagram
    participant caller as Caller
    participant rh as rerank_hits()
    participant ep as _rerank_via_endpoint()
    participant nim as NIM Server

    caller->>rh: query, hits, invoke_url
    rh->>ep: query, documents, endpoint
    ep->>ep: normalize URL → /v1/ranking
    ep->>nim: POST /v1/ranking {model, query:{text}, passages:[{text}], truncate:END}
    nim-->>ep: {rankings:[{index, logit}]}
    ep-->>rh: List[float] scores
    rh-->>caller: hits sorted by _rerank_score

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Prompt To Fix All With AI

This is a comment left during a code review.
Path: nemo_retriever/src/nemo_retriever/rerank/rerank.py
Line: 114-115

Comment:
**Stale `top_n` reference in Returns docstring**

The phrase "Documents not returned by `top_n` truncation receive `-inf`" is stale. The payload no longer includes `top_n` — server-side truncation was removed when the endpoint changed. The `-inf` sentinel now means only that the server didn't return a score for that index (e.g. the server returned fewer items than sent), not that it was `top_n`-truncated.

```suggestion
    List[float]
        Scores aligned with *documents* (higher = more relevant).
        Documents for which the server returns no score receive ``-inf``.
```

How can I resolve this? If you propose a fix, please make it concise.

---

This is a comment left during a code review.
Path: nemo_retriever/src/nemo_retriever/rerank/rerank.py
Line: 14-17

Comment:
**Potentially misleading vLLM version hint after endpoint change**

The module docstring still opens with "calls a vLLM (>=0.14) or NIM server". The vLLM 0.14 reference was meaningful when the endpoint was `/rerank` (vLLM's OpenAI-compatible rerank API). The new `/v1/ranking` endpoint is NIM-specific; it's worth clarifying whether vLLM also exposes this path, or dropping the vLLM qualifier to avoid implying it does.

```suggestion
When ``invoke_url`` is set the actor/function calls a NIM (or compatible vLLM)
server that exposes the NIM ranking REST API. The helper accepts
either a fully qualified ``.../reranking`` URL or a base URL and appends
``/v1/ranking`` automatically::
```

How can I resolve this? If you propose a fix, please make it concise.

_{Reviews (3): Last reviewed commit: "Address greptile comment" | Re-trigger Greptile}

[charlesbluca]

LGTM - mind applying the remaining Greptile suggestion?